Photographic copying



Patented Oct. 29, 1940 PATENT OFFICE.

PHOTOGRAPHIC COPYING Geza Szasz, New York, N. Y., assignor to Electro-Copyst, Inc., New York, N. Y., a corporation of New York ApplicationAugust 30, 1934, Serial No. 742,078. Renewed December 20, 1938. InGermany September 5, 1933 Claims. (Cl. 955) This invention relates tophotographic copying, for instance, of documents having stronglycontrasting lines, and particularly to photographic reflex-copying.

5 Various attempts have already been made to provide photographiccopying, but these have not been successful in practice moreparticularly on the ground of difiiculties encountered in operation.Thus for instance the time taken in making photographic copies hasnecessarily been inconveniently long and moreover known processes havenecessitated the use of a dark room or equivalent precautions to avoidadversely affecting the light-sensitive paper during loading of theapparatus or the actual copying process.

One of the objects of the present invention is to provide a processwhereby reflex copying operations may be carried out in daylight orartificial light and without the aid of a dark room.

A further object is to provide a process whereby reflex-copies may bemade in a relatively short time and free from any image of the structureof the fibres of the paper or other carrier for the 25 sensitisedemulsion, which image in known processes has led to blurring of finelines and speckling of large areas.

Another object of the present invention is to provide a photographicmedium adapted for use in a photographic copying operation carried outunder subdued daylight or ordinary artificial light, the light-sensitivematerial thereof being of such low general light sensitivity as to becapable of being handled in such light without fogging, and beingsensitized to light of long wave length to enable printing by long wavelength light.

With the above and other objects in view the present invention residesin photographic copy- 40 ing involving the steps and featureshereinafter described and claimed in the appended claims.

In carrying out a process according to this invention I employ lighthaving a large long-wave content, for example light obtained from atungsten filament electric lamp fed with over-voltage,

' and cause said light to pass through a filter which absorbs light ofshort wave length, said filtered light then being permitted to passthrough a light 50 sensitive paper capable of reproducing strongcontrasts; on to a document to be copied and thence back on thelight-sensitive surface of said paper, said surface being of low generallight sensitivity and consisting chiefly of silver chloride. Afterexposure, as described, the latent image on the light sensitive paper isdeveloped out and fixed in the usual manner except that no dark room isrequired.

The light-sensitive emulsion includes a sensitiser for light of longwave-length, that is in 5 the yellow and red portions of the spectrum,such as erythrosin, and in order to decrease the general sensitivity ofthe emulsion a densitiser may also be added such for example assaffranine which possesses the additional advantage of be- 1 ingoptically sensitive.

The apparatus for printing according to this invention may comprise abox-like container housing a reflector of rectangular longitudinalcross-section and parabolic transverse cross-section, a glass platelocated over said reflector and forming a working surface, provision forsupporting a tubular electric lamp along the focal line of saidreflector, a light filter for absorbing light of short wave-lengthlocated between said light source and said glass plate and a containerfor light-sensitive paper from which a length of paper may be drawn whenrequired.

The aforesaid box-like container is preferably fitted with a hinged lidcarrying a pressure plate adapted to press the document to be copied andthe light sensitive paper on to the above mentioned glass plate.

The aforesaid glass plate is so mounted in the box-like container thatthe side walls of the latter do not project above the working surface ofthe former and the lid is so mounted that it can be moved into aposition in which it does not project above said surface or it may bemounted so as to be easily removable. In this way provision is madewhereby documents of an area greater than that of said container may becopied.

The aforesaid housing for the light sensitive paper located within themain container includes a slot through which the paper may be drawn andtwo overlapping strips, between which said paper is threaded, cover saidaperture. One of said strips serves as a guide for the paper and theother serves as a knife for severing a length when desired. Theaforesaid slot may be further covered by means of a movable flap so asto afford a further safe-guard against the entry of light.

The filter employed in carrying out my invention is preferably a yellowone although in some cases a red filter may be employed.

In order that my invention may be well understood I will now describeone suitable form of 55 apparatus with reference to the accompanyingdrawing, in which- Figure l is'a cross-section of the apparatus with itslid in a raised position.

Figure 2 is a longitudinal cross sectional viewof the apparatus with thelid closed.

Figure 3 is an enlarged sectional view of a detail 'of the apparatus,

Figure 4 is a longitudinal section of the paper container with the lidraised and Figure 5 is a perspective view of the paper roll.

Referring to the figures the apparatus comprises a portable box-likecontainer I divided into two compartments. In one of these compartmentsa reflector 2 is provided, said reflector being of parabolic transversecross-section and rectangular longitudinal cross-section and extendingthe whole length of the compartment.

A tubular light source 4, controlled by a switch 3, is located on thefocal line of the reflector 2 and may consist of an electricincandescent lamp preferably having a tungsten filament. Said lightsource is fed with over-voltage so that the light contains a largeamount of rays of long wave-length.

The light reflector 2 is covered by a dispersion plate 5 which iscoloured yellow so as to form a filter for any light of shortwave-length issuing from the source 4. Said plate 5 is uniformlyilluminated by means of the reflector 2 and is also illuminated by thedirect rays from the lightsource 4 and I find that owing to theefficiency of the illuminating system and the use of an emulsioncontaining a sensitizer for light of long wave length I can employ lessintense light sources than those hitherto necessary with a consequentreduction in the development of heat.

The top of the box I is covered by a plate 6 of clear glass spaced fromthe dispersion plate 5 and the upper surface of said plate 6 projectsabove the edges of the box. Said plate 6 is secured in an easilyremovable manner by bars I in such a way that its upper face projectsabove the level of said bars. This can be achieved by bevelling the endedges of the plate 6 in the manner shown in Figure 3 of the drawing.

The box I has a hinged lid 8, which can be supported in a verticalposition by means of stays so as to form a screen protecting the plate 5from bright light whilst the sensitised paper is positioned thereon,emulsion uppermost. The aforesaid stays of the lid 8 are releasable, sothat said lid can be moved backwards into a horizontal position in aplane which is lower than that of the upper surface of the plate 6 sothat parts or sections, for instance of maps that are larger than theworking surface of the apparatus can be copied. The application pressurein such cases is applied by any suitable means for example by means ofweights although when copying documents which do not extend beyond thearea of the plate 6 the lid is adapted to provide the necessarypressure. For this purpose said lid carries a plate 9 of glass or metal,the outer face of which is flat and corresponds with the upper surfaceof the plate 6. Behind the rigid plate 9 is a cushion III,

for example of porous rubber, with the aid of which the plate 9 may bepressed elastically against the plate 6. The working surface of theplate 9 is covered with a layer I I of felt or the like form of acontainer I2, the long walls, bottom,

front wall and rear wall of which are firmly connected together. On therear wall a bearing block I3 is secured, which serves as support for thejournal I4 of a paper roll I5. The opposite end of the paper roll I5 hasa square recess I6 into which fits a journal I! provided in the wall ofthe receptacle. The journal I! is mounted in the front wall I8. As thetwo ends of the paper roll I5 are formed differently, the roll cannot bewrongly inserted in the compartment. A locking device I8a is providedfor preventing inadvertent reverse movement of the paper roll I5. Thelid IQ of the compartment containing the paper roll I5 is removable inan upward direction, and is generally secured by screws 20. In the lidI9 a flap 2 I is provided, which is normally pressed under the action ofa spring against the surface of the lid I9. The lid I9 further carries ahalf bearing corresponding to the half bearing of the block I3, and hason its lower surface strips 22 and 23 which engage one over the other.One of. these strips is formed as a cutting off device, and the other asa guide for the paper as it is drawn from the roll I5. The protectivepaper for the roll I5 is folded inwards at its front end and cutobliquely in front. After removing the first Wrappings consisting ofprotective paper, the lightsensitive paper can be drawn oil, asrequired, and separated by the cutting edge of the bar 22. The narrowslit between the bars 22 and 23 is closed in a light-tight manner by theflap 2I, so that on pulling off the paper, only a few millimetres of theunused paper can be reached by light, and these only by a small amountof light. There is consequently no more paper spoiled than is otherwisewasted in cutting. A leaf-spring 24, fastened inside the box, bears withits free end against the point of lead-off of the paper from the rollI5, so that even when the diameter of the roll diminishes, the paper webis held in the desired position, and its unintentional slipping out ofthe slot between the bars 22 and 23 is prevented. The spring 24 can bepressed aside, after lifting up the cover I9, in order to permit of theinsertion of a new paper roll. Said paper roll is fittted by passing therecess I6 over the journal I1, and locating its journal I4 in thebearing block I3. When the cover I9 is put on, the roll I5 is held inthe desired working position and any incorrect fitting of the roll inthe compartment is impossible. Linings 25 which are concentric with thepaper roll I5 are provided inside the box,and prevent the leading end ofthe paper from catching in the inside corners of the box or casing.

The use in combination of the various features described and claimedherein enables reflex copies of a greatly improved quality to beproduced at will either in daylight or artificial light.

I claim:

1. As an article of manufacture, a photographic medium adapted for usein a photographic copying operation carried out under subdued daylightor ordinary artificial light, comprising a carrier and a light-sensitiveemulsion layer coated thereon, the light-sensitive material of saidemulsion consisting chiefly of silver chloride, and said emulsioncontaining a desensitizer rendering the emulsion of such low generallight sensitivity as to be capable of being handled in subdued daylightwithout fogging and containing a sensitizing dye rendering the emulsionsensitive to light of long wave length.

As an article of manufacture, a photographic medium adapted for use in aphotographic copying operation carried out under subdued daylight orordinary artificial light, comprising a carrier and a light-sensitivedeveloping-out emulsion layer capable of reproducing strong contrastscoated thereon, the light-sensitive material of said emulsion consistingchiefly of silver chloride, and said emulsion containing a densensitizerrendering the emulsion of such low general light sensitivity as to becapable of being handled in subdued daylight without fogging andcontaining a sensitizing dye rendering the emulsion sensitive to lightof wave length at least as long as yellow.

3. A photographic reflex-copying process carried out under subdueddaylight or ordinary artiflcial light without the aid of a dark room,said process comprising passing a printing light having a large longwave length content through a carrier bearing a light-sensitivephotographic emulsion layer onto a document to be copied, said documentbeing in direct contact with said emulsion, and reflecting said lightback from said document onto said emulsion and thereby exposing theemulsion, the light-sensitive material of said emulsion consistingchiefly of silver chloride, and said emulsion being rendered of such lowgeneral light sensitivity as to be capable of being handled in subdueddaylight without fogging by the incorporation therein of a desensitizer,and being sensitized for light of long wave length.

4. A photographic reflex-copying process carried'out under subdueddaylight or ordinary artificial light without the aid of a dark room,said process comprising passing a printing light having a large longwave length content through a carrier bearing a light-sensitivephotographic emulsion layer onto a document to be copied, said documentbeing in direct contact with said emulsion, and reflecting said lightback from said document onto said emulsion and thereby exposing theemulsion, the light-sensitive material of said emulsion consistingchiefly of silver chloride, and said emulsion being rendered of such lowgeneral light sensitivity as to be capable of being handled in subdueddaylight without fogging by the incorporation therein of adensensitizer, and being sensitized for light of long wave length by theincorporation therein of a sensitizing dye.

5. A photographic reflex-copying process carried out under subdueddaylight or ordinary artiflcial light without the aid of a dark room,said process comprising passing a printing light having a large longwave length content through a carrier bearing a light-sensitivephotographic emulsion layer onto a document to be copied, said documentbeing in direct contact with said emulsion, reflecting said light backfrom said document onto said emulsion and thereby exposing the emulsion,and then developing the latent image thus formed, the light-sensitivematerial of said emulsion consisting chiefly of silver chloride, andsaid emulsion being rendered of such low general light sensitivity as tobe capable of being handled in subdued dawlight without fogging by theincorporation therein of a desensitizer, and being sensitized for lightof wave length at least as long as yellow by the incorporation thereinof a sensitizing dye.

GEZA SZASZ.

